Process of duplicating talking-machine records.



T. A. EDISON. PROCESS 0E DUPLICATING TALKING MACHINE RECORDS.

- APPLIoATi'oN-FIVLBD mn. 4. 19o?. 975,339.

/Patentea Nov.8,191 o.

` To all l'whom it may concern.'

4Machine, Records,"of which the following riruvsmitns rarer Fries.

'riioivinsa En-IsoNQoi LLEWELLYN PARK, ORANGE, .NEW JERSEY..

. PROC-ESS 0F DUPLICATING TALKING-MACHINE RECORDS-i Y Specication of piane-ation filed March 4,

Be it known that I, THOMAS ALVA EDISON, a citizen of the United States, and a` resident of Llewellyn Park', Orange, county of Essex, and State of New Jersey, have invented' certain new and useful Improvements in Processes of Duplicating Talkinga description. f

My invention relates to an improved proc ess for duplicating talking machine records of the disk type and preferably in which platingthe same to form a. matrix, which 'isA the record itself exists as-a sinuous groove cut or otherwise formed in a wax-like material by the action of a suitable stylus 'actuated by sound waves and vibrating in a plane parallel with the recording surface. At present'such records are duplicated by. first coating the original master with extremely finely divided' graphite and electrothen separated from the master land employed to impress a suitable hot-plastic ma,

vterial which, duri-ng the pressing operation', `takes ,the proper disk-like form. Such a process is objectionable onaccount of the ex- -pense of making the .matrices by electroplating and thenncertainty of that oper- V ation. Furthermore,- in separating the matrix from themaster the latter is generally broken or its record surface injured, and since the life of the matrix is not long, ther surface being in a short ltime a'ected by the hot plastic material, it becomes necessary, before afresh matrix can be secured, to

make a new master, whichv is expensive and tedious.

The; objects of my invention are to pro- .'vide avery cheap and effective process for the purpose, in which electro-.plating is dis-V pensed with, and a very superior and du- -rable matrix is secured so that the resulting p `duplicates are of a 4high order. Furthermore, in the separation of the matrix, the` surface of the .master will lnot be injured in the slightest degree, so that. the master may be preserved indenitely and any .desired'number of matrices made therefrom.

. Brc adly stated the improved process con-J ssts in first coating a suitable master.- (obtained'byrecording upon a wax-like blank inany suitable and ordinary way)` with an excessively thin. layerof extremely finely dii vided material that is notgreatly Water repellent, if at all, then in flowing over the record surface .an enz'mlsion of an extremely g Letters-Patent. PatentedNov. 8, 1910. .1907. seria1N03eo1f3. i

nely divided cement,i l pfr surface, then in separating ,theI matrix from themaster, and in 'nally obtaining vdupli- .cate copies from the matrix, preferably by impressing the same upon and into a suitable hot plastic material, as with the artas In order that the invention may be better understood, attention is directed to the acspecific'ation, and in whlch- Figure l represents a' section of a part of the master on a greatly enlarged scale; Fig.

-preferably one employing stearate of soda, 4and it carries the helical record oove 2 formed by means of any suitable styrus actuated Vby sound vibrations. The record 2 exists preferably as' a sinuous groove as in the it may be of any' other suitable form. Havcoat the same with a material that is not atly vwater repellent, so as to permit the cement emulsion toow regularly over the ously this layer 3 should be excessively thin so as not to appreciably fill up the record groove, and its particles "should excessively., \ne so as not to make the matrix rouln Amaterial adequately meeting these 'con itions is extremely finely divided graphyite' such as now used for coating the master Ato form a conducting film, and which may be applied' to the surfaceanthoroughly and 'carefully rubbed therein'. Y' Instead of graphother suitableinetal, by a'process of *vacuoils deposit, as in connection with the manufacnow practiced with electro-plated matrices.`

2, a similar view on the same scale, of the The master 1 isiof thev usual type, being formed of a suitable Wax-likecompositiomv ordinary disk records of the present day, but.

ing obtained a suitable master, I proceed to vite the master; maybe coated with gold, or im:

v-feral-)ly Portland cement, then in allowingthe cement to' set 4 so as to form a perfect -matrix of the record l companying drawings forming part of this same and take a perfect impression. Obviture -of moldslfromphonograph records. See 2 plained hereafter, said groove ybeing of enormoved, and the matrix is separated from the,

mous depth compared with the record groove. Themaster as so coated and formed 1s now surrounded by a ring or ange 5 and over the record surface I flow a thick emulsion of a suitable hard and smooth cement 6, the

uniform and perfect distribution ofthe cement being possible by reason of the coating 2. Iv prefer forthis purpose, Portland cement reduced to an impalpable powder since the resulting matrix will be' extremely hard-harder in fact than an electro-plated matrix; it will be practically unaffected by the hot plastic material, and itssurface. will be excessively smooth and glazed, so as to permit very erfect records to be impressed 'therefrom.` ther cements may however be used which will not be affected by the hot material, such as' oxychlorid of zinc and magnesia; or if rapid manufacture is important, a quick setting cement may be made, such as is used in dental work, consisting of oxid of zinc and glacial phosphoricacid, which hardens in a few minutes. But all things considered, except for the time required to set, I consider Portland cement, in exceedingly finely divided condition, to be preferable, both because it results in a harder Vland superior matrix and because more perfect records can be made therefrom. After the matrix is set, the ring or ange 5 is remaster, which can be done without injuring the surface of the latter in\any way, so that the master may be preserved and any desired' number of matrices made therefrom. The matrix, which will be formed with a 'cutting flange 7 (corresponding to the groove 4) as will be understood, is now mounted in a suitable press plunger 8, movable ver'a bed 9 which may be heated if desired. On the bed and beneath the matrix, is placed a mass 10.

V.so

of the desired hot plastic material-one employing shellac or so-called button-stock, or other material-and the press plunger 1s forced downward with great pressure, so as to displace the material and squeeze 1t into a disk of the desired thickness, with the record impressed in its surface, as in the usual wa The cutting flange 7 will also partia ly sever the materia sothat when the impressed mass vis removed the superiuousI material may be trimmed olf and the record as and for the purposes set forth.

-2. The process of making a matrix from a d1sk7master formed in a wax-like material,

.which consists in coating the record surface with an excessively thin layer of a material not greatly water-repellent, in flowing thereover a water emulsion of an excessively nely divided cement, in allowing the cement to set and harden, and in separating the resulting matrix from the master, substantially as and for the purposes set forth.

3. The process of making a matrix from a" disk-master formed in a wax-like material, which consistsin coating the record surface with an excessively thin layer of a material not greatly water-repellent, in flowing thereover a water emulsion of excessively finely divided Portland cement, in allowing the cement to'set-and harden, and in separating the resulting matrix from themaster, substantially as set forth.

4. The process of duplicating talking mal .water-repellent, then in owing thereover an emulsion of an excessively finely divided cement, thenin allowing the cement to set and harden, then in separating the. resulting matrix from .the master, and iniinally forcibly impressing the matrix upon a mass of hot plastic material, substantially as set forth.

This specification signed and witnessed this 23rd day of February 1907.

THOS. A. EDISON.

Witnesses:

FRANK L. DYER, ANNA R. KLEHM. 

